I have to say, I do not think that the Ace is lean or thin sounding at all. Now, that may just be my system, or it may be the way my cartridge is set up, and to be honest, I haven't heard many other cartridges to compare it to.
If any thing, I would say the OPPOSITE! The ACE is rich in the bass department, with it's forte being the midrange. I have not heard the Grado, but from everything I read - the grado's generally have great midrange, but aren't great trackers and have rolled off highs and rolled off lows. It's hard for me to back the ACE whole heartedly, but I can say that I have been happy with it. It's a good tracker, it is nicely balanced, and smoothe to my ears.
I would love to hear the blackbird or the dynovector, but for you, they are both over $500, so unless you are willing to buy used, I would count those out, and If I were you, I would be very reluctant to buy a used cartridge. You never know in what condition it will be. That's just me.
Check out the review on Absolute Sounds website:
http://www.avguide.com/products/product-3327/
The reviewer there does mention to be careful to pair it with a medium mass tonearm or it may sound to lean...maybe that is what Audiofiel heard.....